Can't try for baby

I am try to start my sims family and every time I select to try for baby or woohoo they talk and it dissapears and they don't do it. they are both young adults. they currently live in a haunted house in henford-on-bagley. they live on the olde mill hill lot. there are multiple woohoo spots not blocked yet they refuse to woohoo. they have a almost full romance bar.